Variable-pitch pulley



Dec. 1 3, 1938. R BOWEN 2,140,182

VARIABLE-P ITCH PULLEY Filed Dec. 12, 1936 2 Sheets-Sheet 1 7 FIG I, 7 I" 7 W TNESSES: IN V EN TOR:

Russell 77? 501mm L/ y Dec. 13, 1938. I BOWEN 2,140,182

VARIABLEPITCH PULLEY Filed Dec. 12, 1936 2 Sheets-Sheet' 2 FIG: Y 11 i '1' if", i

W TNESSES: l N V EN TOR Russeli 77? 130mm Jim; w. my

Patented Dec. 13, 1938 quire!) STATES.

PATENT OFFICE VARIABLE-PITCH PULLEY Russell H. Bowen, Philadelphia, Pa., asslg'nor to The American Pulley Company, Philadelphia, Pa., a corporation of Pennsylvania Application December 12, 1936, Serial No..115,'498

3Clalms.

This invention relates to variable-pitch pulleys 10 pitch or effective diameter of said pulley, and

locked at the required adjustment.

Another object of the invention is to provide against any tendency to spreading or movement closer together of the respective sheave-forming components.

A further object of the present invention is the provision, in a pulley of the types above indicated, of a co-axial rotative means for effecting variation in the pitch diameter thereof.

Other objects and advantages, more or less ancillary to the foregoing, and the manner in which they are realized, will become apparent from a more complete examination of the following description which, considered in connection with the accompanying drawings, sets forth practical coordinations of the inventive features.

Generally stated, this invention consists of the novel items, combinations of means, and arrangements of parts hereinafter disclosed, illustrated by the drawings, and more concisely expressed in the claims at the conclusion hereof.

In the drawings:

Fig. I is a view showing one form of the improved pulley, partly in elevation and partly in section.

Fig. II is an end view looking in the direction of one of the sheave components of this invention.

Fig. IV is a fragmentary sectional view, taken as indicated by the arrows IV-IV in Fig. IL Figs. V, VI and VII, are views corresponding to Figs. I, II and III, showing an alternative form of the invention; and,

Fig. VTII is a fragmentary sectional view,

taken as indicated by the arrows VIII' --VIII in Fig. VI.

-In the form of this invention featured in Figs.

I-IV, the'improved pulley includes a sleeve hub member I with duplex right and left hand external threads 2, said member being held against rotation on the pulley shaft 3 by means of a spline 4, and secured against shifting axially on said shaft by a set-screw 5 passing through an enlarged head or collar 6 at one end thereof.

Mounted on-the hub member I are a plurality of coaxial sheave units 1 comprising opposinghalf or'counterpart components 8, 9, and In, H which jointly provide V-grooves 12, for as many individual drive belts (not shown). The sheave components 8, 9 have ,right-hand internal threads and the sheave components III, II lefthand internal threads, in engagement with the external. duplex threads 2 of the hub member I. A longitudinally extending key l3, secured by a set-screw H in the axial boss l5 of the sheave component ll, passes through conformative slots IS in the other components 8, 9 and Ill, thereby connecting saidcomponents together and holding them in definite common circumferential relation, but with capacity for simultaneous axial shifting.

As a consequence of the described arrangement, it is possible to concurrently vary the efwithout attendant disaligning of the respectively associated belts, simply by turning the entire assemblage of said units in one direction, or the other, about the hub member I incident to which the components'8, l0 and 9, II will be moved closer together, or further apart, under the action of the duplex screw threads 2.

In order to prevent accidental displacement of the sheave components 8-ll in adjusted positions by positively preventing-relative movement,.a pair of 'stop screws l1, I! are provided, said screws being preferably carried by the endmost componentll. As shown in Fig. I, the shank of the stop screw 11 threadedly engages a tapped aperture IS in the component II and bears against the companion sheave component 8; while the stop screw I8 is free in a smooth aperture 20, Figs. III and IV, of the component i l, with its head 2| bearing against a shoulder 22 in said aperture 20 andits shank threadedly fective diameters of the severalsheave units 1 the other units is positively prevented through the medium of the key i3.

In the alternative embodiment of the invention illustrated in Figs. V-VIII, the sheave components 8a, 9a and la, Ha, respectively, have left and right-hand internal threads in engagement with external duplex threads 20. of the sleeve hub member la on the pulley shaft 311, said sheave components being, in this case, connected with capacity for shifting axially, by a pair of pins l3a passing through aligned holes 16a in them. Mounted on the hub member la, respectively adjacent the outermost sheave components 8a, Ila,v

are nut collars 25, 26 both having a left-hand internal thread in engagement with the external duplex thread 211. of said hub member. Threadedly engaged in tapped apertures 19:; of the sheave component Illa are a pair of screws lla, whereof the diametrically reduced plain ends 21 pass through smooth apertures 28 in the sheave component 8a and abut the contiguous .face of the nut collar 25. To adjust the pulley in this case for variation in the efiective diameter of the sheaves la, the nut collars 25, 26 are backedoff and the sheave assembly thereupon rotated bodily about the sleeve hub la. in one direction, or the other, to bring the sheave components 8a-|'la either closer together, or further apart. After the desired adjustment has been obtained, the nut collar 26 is brought into jamming relation withthe'face of the hub I50. of the sheave component Ha, and the nut collar 25 into jamming relation with the shank ends 21 of the screws lla. Due to the reversed internal threading of the sleeve component lla and the jamming nut collar 26, said component is locked against the possibility of independent rotation on the hub member la. Likewise due to the re versely pitched threads of the sheave component Ina carrying the screws Ha and the nut collar 25, said component is likewise locked against rotation on the hub member la. In order to 'facili-.

tate the adjustment, the sheave component I la and the nut collars 25, 26 are respectively pro-- vided with spanner wrench holes 29, 30 and 3i.

While specific embodiments of the invention have been illustrated and described, it is to be understood that alteration in the details of construction may be effected without departing from the spirit and scope of said invention as indicated in the following claims.

Having thus described my invention, I claim:

1. A variable-pitch diameter groove pulley comprising a hub member with external opposing duplex threads, groove-forming side components having internal threads in engagement with the hub member threads, means holding all of said components in definite common relation circumferentially with capacity for simultaneous turning in one direction or the other to efiect axial adjustment towards and away from each other, and means for locking the groove-forming components including reactive stop screws, one of which threadedly engages through one of the side components into abutment with the companion component, and the other screw passes freely through the first mentioned component into threaded engagement with the second named component, whereby all of the groove forming components are positively arrested against relative movement.

2. A variable-pitch diameter groove pulley comprising a hub member with external right and left-hand duplex threads, a series of opposing coaxial groove-forming side components having alternately reversed internal threads in engagement with the hub member threads, means holding all of said components in definite circumferential relation with capacity for concurrent rotation in one direction or the other to effect their axial movement toward or away from each other, said means consisting of a longitudinal key secured to one groove-forming side component and passing through conformative slots in the other components, and means for positively locking the groove-forming components, at the requisite adjustment, including a pair of reactive stop screws, one of which threadedly engages through one or the pulley outer components into abutment with the companion component, and the other of said screws passes freely through the first mentioned groove-forming component and threadedly engages in the second named component whereby all of the groove forming components are concurrently bound to the associated hub member thread portions.

3. A variable-pitch groove pulley as defined in claim 2 in which the series of groove-forming components are held in definite circumferential relation by pins fitting aligned holes through said series, nut collars with internal left-hand threads engage the hub member ends, and stop screws threadedly coact with one groove-forming component and pass through smooth apertures in the companion component into jamming abutment with one of the hub end collars.

RUSSELL I-I. BOW'EN. 

